Laravel_Query_String_Parameters_Guard.md

<?php

/**
 * AppRquest Class
 * File: App/Http/Requests/AppRequest.php
 */
 
namespace App\Http\Requests;

use Illuminate\Http\Request;

class AppRequest
{
	
	protected $req;

	public function __construct(Request $req)
	{
		$this->req = $req;
	}
	
	/**
	 * Proxy the rest of the methods calls to the Request Class
	 */
	public function __call($method, $args)
	{
		return call_user_func_array( [ $this->req, $method ], $args );	
	}
	
	/**
	 * Proxy writing data to inaccessible properties to the Request Class
	 */
	public function __set($name, $value)
	{
		$this->req[$name] = $value;
	}

	/**
	 * Proxy reading data from inaccessible properties to the Request Class
	 */
	public function __get($name)
	{
		return $this->req[$name];
	}

	/**
	 * Decorate the query method
	 */
	public function query($key, $default = null, $cb = null)
	{
		
		
	    $value = $this->req->query($key, $default);
	    
	    if( null === $cb && is_numeric($value) && is_numeric($default) )
	    {
	        $cb = function($value, $default) {
	            
	            if( $value > $default )
	                return false;
	                
	            return true;
	            
	        };
	    }

	    if( is_callable($cb) && !$cb($value, $default) )
	    {
	        return $default;
	    }

	    return $value;	
	}
	
}


/**
 * Register AppRquest Class
 * File: App\Providers\AppServiceProvider
 */

use App\Http\Requests\AppRequest;

public function register()
{ 
    $this->app->bind(AppRequest::class, function(){
        return new AppRequest( request() );
    });
}

How to use

1. By default the Default Validation Closure will be used if the Query String Patameter & the Default Value are both numerical.
2. The Query String Patameter value will be returned if there are no validation roles passed.
3. The Default Validation Closure will return the default value if the Query String Patameter greater than the Default Value

Example:

http://localhost:8000/users?limit=1 - $limit = 1
http://localhost:8000/users?limit=2 - $limit = 2
http://localhost:8000/users?limit=3 - $limit = 2
http://localhost:8000/users?limit=9 - $limit = 2

use App\Http\Requests\AppRequest;
use App\User;

Route::get('/users', function(AppRequest $req){

	$limit = $req->query('limit', 2);
	return User::paginate($limit);

});

Custom Validation

You can pass a closure as a third parameter to perform a custom validation

http://localhost:8000/users?limit=1   - $limit = 1
http://localhost:8000/users?limit=10  - $limit = 10
http://localhost:8000/users?limit=99  - $limit = 99
http://localhost:8000/users?limit=100 - $limit = 100
http://localhost:8000/users?limit=101 - $limit = 100

Example:

Route::get('/users', function(\SharedKernel\Http\AppRequest $req){

	
	// This will guard the Query String Parameter by returning the default value if
	// the limit Query String Parameter is greater than 100
		
	$limit = $req->query('limit', 100, function($value, $default){

		if( $value > 100 )
		    return false;

		return true;
	});

	return App\User::paginate($limit);

});